At present, there are mainly two solutions for multi-SIM terminals on the market: multi-SIM multi-standby and multi-SIM multi-active. The former uses one baseband chip, one radio frequency chip, and one memory that form one system, and controls, by using software, the chips to constantly switch between multiple networks, so as to simultaneously search for and camp on networks used by multiple user cards, for example, networks used by a SIM card, a universal subscriber identity module (USIM) card, and a user identity module (UIM) cards, while the latter simultaneously uses multiple systems each including one baseband chip, one radio frequency chip, and one memory system, and is equivalent to combining multiple complete terminal mainboards in one terminal. When one user card is in a conversation state, another user card of a multi-SIM multi-standby terminal inevitably drops from a network, while another user card of a multi-SIM multi-active terminal can still be connected by dialing. Therefore, the multi-SIM multi-active terminal will inevitably become a mainstream on the market.
According to the prior art, as shown in FIG. 1, at present, call management links, which start from a user card 1 to a user card N at the bottom, pass through a wireless interface module 1 to a wireless interface module N respectively and a call management module 1 to a call management module N respectively, and reach an uppermost application 0, of a multi-SIM multi-active terminal are multiple entirely independent control paths that are unrelated to each other, and it may be considered that multiple independent terminals are merely integrated together by the uppermost application by force for displaying. In addition, in the prior art, a network side performs call management for multiple user cards served by a same network.
Therefore, the prior art has the following disadvantages. The network side cannot learn a call status of a user card that uses another network, and cannot perform centralized call management for multiple user cards served by different networks; therefore, the multiple user cards served by different networks cannot implement a conference call.